What do you mean by the anomalous expansion of water?

Explanation

### Step-by-Step Solution

1. **Definition of Anomalous Expansion**: The term "anomalous expansion" refers to the unusual behavior of a substance when it expands or contracts with temperature changes. In the case of water, it behaves differently compared to most other substances.

2. **Normal Expansion Behavior**: Typically, most substances contract when cooled and expand when heated. This is due to the decrease in kinetic energy of the molecules, which come closer together as the temperature drops.

3. **Water's Unique Behavior**: Water, however, exhibits a unique property. When it is cooled from 4°C to 0°C, instead of continuing to contract, it actually expands. This means that water becomes less dense as it approaches freezing.

...